1. Field of the Invention
The present invention relates to multi-layered LC composite components, and more particularly relates to multi-layered LC composite components included in high-frequency bands.
2. Description of the Related Art
A conventional multi-layered LC filter is shown in each of FIGS. 15 and 16. As shown in FIG. 15, a multi-layered LC filter 1 includes a ceramic sheet 4 having inductor patterns 7 and 8 and frequency-adjusting capacitor patterns 9 and 10 provided thereon, and ceramic sheets 3 and 5 having shield patterns 12 and 13 provided thereon, and a ceramic sheet 2.
The ceramic sheets 2 to 5 are laminated and subsequently integrally fired to define a multi-layered structure 15 shown in FIG. 16. On the multi-layered structure 15, an input terminal 16, an output terminal 17, and ground terminals G1 and G2 are provided. The input terminal 16 is connected to a leading portion 7a of the inductor pattern 7. The output terminal 17 is connected to a leading portion 8a of the inductor pattern 8. The ground terminal G1 is connected to an end of each of the frequency-adjusting capacitor patterns 9 and 10 and the shield patterns 12 and 13. The ground terminal G2 is connected to a grounded end portion of each of the inductor patterns 7 and 8 and the other end of each of the shield patterns 12 and 13.
In the above LC filter 1, both an inductor defined by the inductor pattern 7 and a capacitor defined by the frequency-adjusting capacitor pattern 9 opposed to an open end portion of the inductor pattern 7 constitute an LC resonator Q1. Similarly, both an inductor defined by the inductor pattern 8 and a capacitor defined by the frequency-adjusting capacitor pattern 10 opposed to an open end portion of the inductor pattern 8 constitute an LC resonator Q2.
When the GHz-band LC filter 1 having the structure shown in each of FIGS. 15 and 16 is produced, an attenuation pole is provided on the high-frequency side of a central frequency. However, to increase the amount of attenuation in the proximity of the central frequency, when another attenuation pole is added on the high-frequency side of the central frequency, for example, in the proximity of a central frequency F0+0.12 GHz, it is not possible to achieve the increased attenuation. In addition, when a plurality of attenuation poles is added in the proximity of the central frequency, increased insertion loss occurs.
To overcome the above-described problems, preferred embodiments of the present invention provide a multi-layered LC composite component that greatly increases the amount of attenuation in the proximity of a central frequency without increasing an insertion loss.
According to a first preferred embodiment of the present invention, a multi-layered LC composite component includes a multi-layered structure including laminated insulating layers, a plurality of inductors and a plurality of capacitors provided inside of the multi-layered structure, a plurality of LC resonators defined by the plurality of inductors and the plurality of capacitors, wherein an end of each inductor conductor constituting the plurality of inductors is electrically connected via a connecting electrode, and the end of each inductor conductor is grounded via a capacitor defined by capacitor electrodes, one of which is the connecting electrode.
Furthermore, according to a second preferred embodiment of the present invention, a multi-layered LC composite component includes a multi-layered structure including laminated insulating layers, a plurality of inductors and a plurality of capacitors provided inside of the multi-layered structure, a plurality of LC resonators defined by the plurality of inductors and the plurality of capacitors, wherein the plurality of inductors is defined by via holes which are connected in a laminating direction of the insulating layers, an end of the respective inductors is electrically connected via a connecting electrode, the end of the respective inductors is grounded via a capacitor defined by capacitor electrodes, one of which is the connecting electrode, and the other end of the respective inductors is electrically connected to a capacitor electrode of the respective capacitors of the LC resonators.
The ends of the inductor conductors are short-circuited and comb-line coupled to each other by the connecting electrode, and are also grounded via the capacitor. With this arrangement, a plurality of attenuation poles is provided in the proximity of a central frequency, thereby the attenuation characteristics in the proximity of the central frequency are greatly improved.
Other features, characteristics, elements and advantages of the present invention will become apparent from the following description of preferred embodiments thereof with reference to the attached drawings.